Here's a composition, courtesy of Steve (@smokris). It first grabs all the frames in the animated GIFs. On each Requested Frame event, it selects the frame for each movie for the current time (looping) and displays the frames in a grid.
I may be very very wrong here but I can't figure out a way to automatically do this using "Process list" neither.
I guess Allow changing single-value ports to accept lists (turn most nodes into iterators) will allow that.